A monofilament formed of a vinylidene fluoride resin is used as a raw material for a fishing line or a fishing net, because the monofilament has excellent physical and chemical properties, inter alia, excellent mechanical strength and durability, and exhibits least deterioration in strength while immersed in water, due to substantially no swelling with water. Recently, fishing with a lure or with a casting net has become a popular sport, as part of the trend towards more and more people enjoying outdoor life. In such fishing, a spinning-type reel is predominantly employed. Therefore, desirable properties of a fishing line employed in such fishing are (1) excellent transmission of a strike; (2) flexibility and curling that is easy to relieve during use: and (3) excellent strength characteristics, particularly high tensile strength when tied.
There exists demand for a fishing line that completely satisfies all the above properties or a fishing line that satisfies all the above properties to a considerable degree, one of the properties predominating so as to suit a specific method of fishing.
In view of the foregoing, an object of the present invention is to provide a monofilament formed of a vinylidene fluoride resin having a feature that undesirable curling is difficult to occur and, even when curling occurs, it can readily be relieved so that the monofilament returns to the initial state. Another object of the invention is to provide a fishing line formed of the monofilament. Still another object of the invention is to provide a fishing line formed of the monofilament for lure fishing.
The present inventors have conducted earnest studies, and have found that a monofilament formed of a vinylidene fluoride resin having a ratio of the elastic modulus at a certain elongation to that at another elongation that falls within a specific range and an elastic modulus at a specific elongation that falls within a specific range exhibits a feature that undesirable curling is difficult to occur and, even when curling occurs, it can readily be relieved so that the monofilament returns to the initial state. The present invention has been accomplished based on this finding.